The cotton fibers pressed into bales must, until they are capable of being spun, not only be brought from their irregular compressed position but also freed from all types of impurities. In the bale opening machine, the compressed cotton must be opened into flakes and transferred by means of a current of delivery air into a cleaning machine. Depending on the degree of contamination, this is a fine or coarse cleaning machine, whereby both are used as a rule. The present invention provides a device which is preferably used in coarse machines. However, it can also be used in an appropriate form in fine cleaning machines.
In cleaning machines of this type, the flakes are preponderantly opened to increasingly small collections of fibers, which are still flakes, whereby loose foreign particles separate from the composition and fall out. The opening takes place exclusively in a type of plucking and beating operation which is effected by means of rapidly revolving toothed rollers and beater rods. This rapid rotary flow, together with the inflow and outflow currents cause dynamically produced air currents, which are indeed drawn into the cleaning process but are not decisive in their total effect. This is one reason, which according to each phase of the operation, a comparatively large number of good fibers are excluded from the process and, if necessary, must go through a recycling process.